It is known to coat substrates, e.g., an open weave substrate, e.g., one formed of polyester, polyamide, or a combination thereof, with a plasticized vinyl chloride polymer to form a coated fabric which can be used as single-ply roofing, in air ducts, as a pond liner, as a tarpaulin, as a mining belt, and the like. In order to enhance the adhesion of the coating of plasticized vinyl to the chosen substrate, it has been proposed to use, as an adhesive, a prepolymer containing at least 2% of isocyanate groups (e.g., U.S. Pat. No. 4,806,414). This approach has been criticized, for example, as posing a potential health danger to persons coming in contact with the adhesive (see U.S. Pat. No. 4,806,414 at Col. 1, lines 35-39).
Various disclosures exist in the prior art dealing with polyketone adhesives. U.S. Pat. No. 3,808,288 describes a pressure sensitive adhesive containing an epichlorohydrin polymer and a selected polyketone resin which is described as being the condensation polymer of one or more types of ketone with a lower aliphatic aidehyde. This composition can be used to form a pressure sensitive adhesive on a number of flexible backings (see Col. 2, lines 24-40).
More recent patents have indicated that the above type of polyketone-containing adhesive is deficient in a number of aspects (e.g., see Col. 2, lines 34-43 of U.S. Pat. No. 4,871,618 and Col. 2, lines 36-45 of U.S. Pat. No. 4,880,904) and have suggested use of certain polyketone structural adhesives for certain end uses. These adhesives are hot melt adhesives intended to be used on such substrates as aluminum, mild steel, cold rolled steel, resin coated steel, and on polymer substrates.